Biomedical subjects

C Gentile

Publications and source records attributed to C Gentile.

At least 19 recordsLinked to original sources

PubMed2006

Cytoprotective effects of the antioxidant phytochemical indicaxanthin in beta-thalassemia red blood cells.

Antioxidant phytochemicals are investigated as novel treatments for supportive therapy in beta-thalassemia. The dietary indicaxanthin was assessed for its protective effects on human beta-thalassemic RBCs submitted in vitro to oxidative haemolysis by cumene hydroperoxide. Indicaxanthin at 1.0-10 microM enhanced the resistance to haemolysis dose-dependently. In addition, it prevented lipid and haemoglobin (Hb) oxidation, and retarded vitamin E and GSH depletion. After ex vivo spiking of blood from thalassemia patients with indicaxanthin, the phytochemical was recovered in the soluble cell compartment of the RBCs. A spectrophotometric study showed that indicaxanthin can reduce perferryl-Hb generated in solution from met-Hb and hydrogen peroxide (H2O2), more effectively than either Trolox or vitamin C. Collectively our results demonstrate that indicaxanthin can be incorporated into the redox machinery of beta-thalassemic RBC and defend the cell from oxidation, possibly interfering with perferryl-Hb, a reactive intermediate in the hydroperoxide-dependent Hb degradation. Opportunities of therapeutic interest for beta-thalassemia may be considered.

Antioxidants↗

PubMed2005

Isolation of a fragment homologous to the rp49 constitutive gene of Drosophila in the Neotropical malaria vector Anopheles aquasalis (Diptera: Culicidae).

The constitutive ribosomal gene rp49 is frequently used as an endogenous control in Drosophila gene expression experiments. Using the degenerate primer PCR technique we have cloned a fragment homologous to this gene in Anopheles aquasalis Curry, a Neotropical vector of malaria. In addition, based on this first sequence, a new primer was designed, which allowed the isolation of fragments of rp49 in two other species, Aedes aegypti (Linnaeus) and Culex quinquefasciatus Say, suggesting that it could be used to clone fragments of this gene in a number of other mosquito species. Primers were also designed to specifically amplify rp49 cDNA fragments in An. aquasalis and Ae. aegypti, showing that rp49 could be used as a good constitutive control in gene expression studies of these and other vectorially important mosquito species.

Aedes↗

PubMed2004

Melatonin reduces oxidative stress in surgical neonates.

BACKGROUND/PURPOSE: Cytokines are inflammatory mediators found in the circulation after surgery. Newborns have less protection against oxidation and are very susceptible to free radical oxidative damage. Melatonin has been reported recently to reduce oxidative stress in neonates with sepsis, asphyxia, and respiratory distress. The aim of this study has been to determine if melatonin would lower interleukin (IL)-6, IL-8, tumor necrosis factor alpha (TNF-alpha) and nitrite/nitrate (NOx) levels and modify serum inflammation parameters, improving the clinical course of surgical neonates. METHODS: Ten newborns (group 1), 5 with surgical malformations and respiratory distress (group 1a) and 5 with isolated abdominal surgical malformations (group 1b) received a total of 10 doses of melatonin (10 mg/kg) at defined times interval for 72 hours. The treatment was started within 3 hours after the end of surgery. Ten surgical neonates (group 2), did not receive melatonin. Twenty healthy neonates (group 3) served as control. Blood samples were collected at the end of operation; before treatment with the antioxidant; and 24 hours 72 hours, and 7 days after start of treatment with melatonin or placebo, respectively. RESULTS: Postoperative value of cytokines and NOx levels of groups 1 and 2 were significantly higher than group 3. Compared with group 1b, group 2 displayed significantly higher cytokines and NOx levels at 24 hours, 72 hours, and at 7 days. In group 1a the immediate postoperative values of cytokines were significantly higher than group 1b and group 2, but a significant improvement was observed after administration of melatonin with significantly lower levels of IL-6 and IL-8 with respect to group 2. An improvement of clinical outcome was observed by progressive reduction of clinical parameters of inflammation. CONCLUSIONS: Melatonin reduces cytokines and NOx levels showing potent antioxidant properties with improvement in clinical outcome. Further studies are warranted to define, on larger numbers, the role of melatonin in surgical patients.

Female↗

PubMed2004

Antioxidant betalains from cactus pear (Opuntia ficus-indica) inhibit endothelial ICAM-1 expression.

It has been suggested that some pigments would have antioxidant properties and that their presence in dietary constituents would contribute to reduce the risk of oxidative stress-correlated diseases. Among others, inflammatory response depends on redox status and may implicate oxidative stress. Vascular endothelial cells are a direct target of oxidative stress in inflammation. We have tested the impact of the free radical scavenger and antioxidant properties of betalains from the prickle pear in an in vitro model of endothelial cells. Here we show the capacity of betalains to protect endothelium from cytokine-induced redox state alteration, through ICAM-1 inhibition.

Anti-Inflammatory Agents↗

PubMed2003

The chemistry of melatonin's interaction with reactive species.

Melatonin has been shown to be an effective antioxidant in a number of experimental models both in vitro and in vivo. Considering the data available, it is now clear that the indoleamine is involved in antioxidative mechanisms more complex than originally envisaged. These range from the direct radical scavenging of a variety of radicals and reactive species to the control and/or modulation of a number of processes which may trigger a redox imbalance between antioxidant and prooxidant species. This review focuses on the direct radical scavenging activity of melatonin and provides a summary of the mechanisms of the reactions between the indoleamine and reactive species in pure chemical solutions. These actions likely account for at least some of the protective actions of melatonin under conditions of high oxidative stress.

Animals↗

PubMed2003

Increased resistance to oxidation of betalain-enriched human low density lipoproteins.

Betalains are natural pigments recently considered as compounds with potential antioxidative properties. In this work, ex vivo plasma spiking of pure either betanin or indicaxanthin, followed by isolation of low density lipoprotein (LDL), and measurement of its resistance to copper-induced oxidation, has been used to research if these betalains can bind to LDL and prevent oxidation of LDL lipids. When pooled human plasma from 10 healthy volunteers was incubated in the presence of 25-100 microM either betanin or indicaxanthin, incorporation of both compounds in LDL was observed, with a maximum binding of 0.52 +/- 0.08, and 0.51 +/- 0.06 nmoles of indicaxanthin and betanin, respectively, per mg LDL protein. Indicaxanthin-enriched and betanin-enriched LDL were more resistant than homologous native LDL to copper-induced oxidation, as assessed by the elongation of the induction period. The incorporated indicaxanthin, however, appeared twice as effective as betanin in increasing the length of the lag phase, while both compounds did not affect the propagation rate. Both betalains were consumed during the inhibition period of lipid oxidation, and delayed consumption of LDL-beta carotene. Indicaxanthin, but not betanin, prevented vitamin E consumption at the beginning of LDL oxidation, and prolonged the time of its utilization. The resistance of LDL to oxidation when vitamin E and indicaxanthin acted separately in a sequence, was lower than that measured when they were allowed to act in combination, indicating some synergistic interaction between the two molecules. No prooxidant effect over a large concentration range of either betanin or indicaxanthin was observed, when either betalain was added to the LDL system undergoing a copper-induced oxidation. These results show than indicaxanthin and betanin may bind to LDL, and are highly effective in preventing copper-induced lipid oxidation. Interaction with vitamin E appears to add a remarkable potential to indicaxanthin in the protection of LDL. Although molecular mechanisms remain uncompletely understood, various aspects of the action of betanin and indicaxanthin in preventing LDL lipid oxidation are discussed.

Antioxidants↗

PubMed2003

Preliminary report on nitric oxide-mediated oxidative damage in adolescent varicocele.

BACKGROUND: The current study was designed to characterize the process of nitric oxide (NO) and peroxynitrite generation through the determination of nitrotyrosine concentration in the dilated veins of varicoceles in adolescents. METHODS: Ten adolescents with a median age of 13 years (range 12-17) affected by a left idiopathic varicocele (grade II and III) were studied. Whole blood samples were withdrawn from a peripheral vein at time of induction of anaesthesia, and from a dilated spermatic vein before ligation. Peripheral blood samples from five adolescents undergoing minor surgical procedures were used as controls. The nitrotyrosine concentration was evaluated by a sandwich enzyme-linked immunosorbent assay (ELISA), using a monoclonal anti-nitrotyrosine antibody and Western blot analysis. RESULTS: Plasma nitrotyrosine concentrations were significantly greater in the spermatic vein when compared with the peripheral vein (P = 0.031). Nitrotyrosine in plasma of controls did not show any significant difference in comparison with peripheral samples from varicocele patients. Western blot analysis confirmed the above data. CONCLUSIONS: In adolescents with a varicocele, there is an increase in nitrotyrosine concentration within the spermatic vein that can cause protein nitration and cytotoxicity via its reaction with various molecular targets. This could have repercussions on both sperm and testis function. We conclude that an oxidative stress status is present and should be considered as an indication for varicocele treatment in the adolescent.

Adolescent↗

PubMed2002

Protective effect of melatonin against cytotoxic actions of malondialdehyde: an in vitro study on human erythrocytes.

Malondialdehyde (MDA), a by-product of the oxidation of polyunsaturated fatty acids, is strongly cytotoxic. Here we report the in vitro ability of melatonin to protect intact human erythrocytes against the damage induced by the exposure to MDA. MDA at 20 microM caused marked variations in the red blood cell (RBC) membrane. High molecular weight fluorescent adducts were formed within minutes with membrane proteins. A 6-hr incubation led to the oxidation of membrane lipids, as reflected by the formation of conjugated diene (CD) lipid hydroperoxides and oxidation of vitamin E, and to an increase of the high molecular weight fluorescent adducts, which were an indication of MDA finally generated in the cells. Functional damage to the membrane was evident as a leakage of K+ ions into the incubation medium, and an increased resistance to osmotic lysis. A time-dependent hemolysis was observed by exposure of RBCs to 20 microM MDA for 6-12 hr. Melatonin was not a substrate for MDA, therefore it was not able to prevent the early formation of the adducts from the reaction of the MDA in the medium with membrane proteins. Melatonin, however, concentration-dependent prevented the formation of CD lipid hydroperoxides. As a consequence of counteracting the membrane lipid oxidation, the indoleamine prevented the loss of vitamin E and the increase of the fluorescent proteinaceous adducts observed after a 6-hr exposure to MDA. Melatonin also inhibited the K+ loss and returned to normal the osmotic resistance of the erythrocyte in the osmotic fragility test. By protecting membrane lipids and proteins, melatonin effectively prevented the MDA-induced time-dependent hemolysis. In the light of the known radical scavenging properties of melatonin, mechanisms of the cytoprotective effects of melatonin in our system are discussed.

Cells, Cultured↗

PubMed2002

Monocyte and neutrophil activity after minor surgical stress.

BACKGROUND/PURPOSE: Surgical stress produces changes in the immune status of patients. In adults, major surgery causes immunosuppression, whereas minor operations stimulate immune responses. In children, the immunologic response to surgery has not been elucidated completely. The authors investigated the effects of minor surgery on immune response by analyzing neutrophil and monocyte phagocytosis and oxidative burst activity. METHODS: Sixteen children undergoing elective minor surgery were enrolled. Blood samples were collected before the operation (at time of induction of anesthesia), at the end of operation, and 72 hours after surgery. Neutrophil and monocyte phagocytosis and oxidative burst activity were studied using a flow cytometric method. RESULTS: Phagocytosis and oxidative burst increased significantly at the end of the operation, both in neutrophils (7.4% and 14.3%, respectively) and monocytes (11.6% and 27%, respectively). The increase was only significant for monocytes (17.5%) 72 hours after surgery. White cell count did not show any significant changes. There was no significant correlation between phagocytosis, oxidative burst activity, and white cell count or neutrophil and monocyte count. CONCLUSIONS: This study shows that minor surgery in children induces immune activation by increasing neutrophil and monocyte phagocytosis and oxidative burst activity. Further studies are required to understand the molecular basis of these findings.

Adolescent↗

PubMed2002

Protective role of the complement regulatory protein human CD-55 in cardiac xenograft: a descriptive study and a revision of the literature.

The limited and inadequate availability of organs from human donors has resulted in the utilisation of xenografts as an alternative tool. Nevertheless, hyperacute rejection (HAR) following xenograft determines the loss of the transplanted organ. The "primum movens" is the activation of the complement pathway mediated by the binding of natural xenogenic antibodies to the endothelium of the graft, followed by the lysis of the endothelial cells with subsequent oedema, thrombosis and necrosis of the transplanted organ. In this work we describe morphological and biomolecular observations of isolated human-decay accelerating factor (h-DAF, CD55) transgenic pig hearts, after perfusion for four hours with human blood. H-DAF is a membrane glycoprotein inhibiting the complement activation in humans. We describe considerably reduced damages in transgenic hearts, compared to controls. The cardiac function resulted preserved. Our data are in agreement with what was already shown by other groups using different experimental models. In conclusion, we encourage the use of new sources of transgenic animals, pointing out the importance of morphological analysis in evaluation of xenograft.

Animals↗

PubMed2001

Nitric oxide synthase patterns in normal and varicocele testis in adolescents.

OBJECTIVE: To determine if the testes of normal adolescents can produce nitric oxide (NO), by assessing NO synthase (NOS) activity, and whether this activity changes in adolescents with left idiopathic varicocele. PATIENTS AND METHODS: After obtaining informed consent, testicular biopsies were obtained from eight adolescents (mean age 16.4 years; controls) who underwent surgery for inguinal hernia or hydrocele, and from 20 adolescents (mean age 16.2 years) operated for left idiopathic varicocele. Inducible and endothelial NOS (iNOS and eNOS) isoforms were investigated in the biopsy specimens by immunohistochemical localization and Western blot analysis using specific fluorescein-conjugated antibodies. RESULTS: Both normal and pathological samples expressed eNOS at the level of vessels and Leydig cells. The iNOS was expressed in Leydig cells of normal testes and over-expressed in Leydig cells of varicocele testes. CONCLUSION: Leydig cells of adolescent testes constitutively express iNOS. Under pathological conditions, e.g. varicocele, iNOS is up-regulated and is a possible source of NO overproduction. These results could be useful in explaining the pathogenesis of both testis and sperm dysfunction in varicocele.

Adolescent↗

PubMed2001

Nitric oxide production is increased in the spermatic veins of adolescents with left idiophatic varicocele.

BACKGROUND/PURPOSE: The existence of an excessive release of nitric oxide (NO) within dilated spermatic veins has been recorded in adults with varicocele suggesting a high oxidative stress. The authors investigated whether NO overproduction is already present in the dilated veins of adolescent varicocele and which enzymatic isoforms in the spermatic vein could be expressed. METHODS: The study group consisted of 10 adolescent patients affected by left idiophatic varicocele of grade II and III. The increase in NO production was established by determination of serum concentration of L-hydroxyarginine (L-NHA) and Nitrite/nitrate (NOx). Both endothelial and inducible NOsynthase (NOS) were investigated by Western blot analysis and by immunohistochemical localization using specific monoclonal fluorescein conjugated antibodies. RESULTS: Serum L-NHA levels were significantly greater in the spermatic veins when compared with the peripheral veins 176.8 +/- 32.3 micromol/L versus 3.38 +/- 0.64 micromol/L (P =.0004 Similarly, NOx levels were increased, respectively, 68.2 +/- 16.7 nmol/mL versus 12.9 +/- 2.65 nmol/mL (P =.029). Endothelial NOS was localized in the spermatic vein of varicocele patients, but not overexpressed; the inducible isoform was not detected. CONCLUSIONS: Adolescents with varicocele already present an increase in NO within dilated veins. The dilated spermatic vein is not the major source for the increase in NO level. These results could have an implication in the natural history of adolescent varicocele and in programming the ideal time for surgical treatment.

Adolescent↗

PubMed2001

Peptic ulcer bleeding: comparison of two hemostatic procedures.

OBJECTIVE: Bleeding is a serious complication of peptic ulcer. Endoscopic injection therapy is accepted as a homeostatic endoscopic treatment in acute nonvariceal of upper GI hemorrhages, particularly in bleeding peptic ulcers. The risk of rebleeding is predicted by the endoscopic appearance of ulcer features classified according to Forrest's criteria. METHODS: Two hundred twenty-three patients were selected from 1,003 emergency upper endoscopies for GI bleeding. According to Forrest's criteria, 99 well-matched patients with ulcers F1 and F2 were considered at risk of rebleeding; 54 patients (group A) received local ulcer injection of epinephrine solution 1:10,000, whereas (group B) patients were treated with local epinephrine injection and then with endoscopic Hemoclips. (1) We considered the control of bleeding, the number of rebleeding episodes, the need for emergency surgery, and mortality. RESULTS: Bleeding ulcers stopped completely in 83.3% group A patients, and in 95.6% group B patients (p = not significant). In a subset of F1b patients the rebleeding rate was 31 % for group A and 0% for group B (p < 0.05). There was no mortality as a result of the procedure. There was a trend toward reducing surgery in favor of the combined therapy (0% vs 7.4%). No differences were found in transfusion requirements or mean hospitalization days. CONCLUSIONS: We conclude that endoscopic injection of l:10,000 epinephrine solution alone and epinephrine solution plus application of Hemoclips are equivalent therapies in treating bleeding and rebleeding from peptic ulcers. There was no difference between therapies in terms of need for surgery or mortality. Possibly combination therapy is more effective in treating ulcers that are actively oozing.

Adolescent↗

PubMed2001

[Ecology of mosquitoes in areas of the National Park of "Serra da Bocaina", Brazil: II - Monthly frequency and climatic factors].

OBJECTIVE: To establish the influence of climatic factors on the monthly frequency of mosquito fauna in areas of the National Park of Serra da Bocaina, Brazil. METHODS: Human bait collections were conducted once a month, in diurnal and nocturnal hours, throughout 24 months, from January 1991 to December 1992. RESULTS: A total of 11,808 adult mosquitoes belonging to 28 different species were collected. Anopheles cruzii, Runchomyia reversa, and Ru. frontosa were the most commonly found species each month. An. cruzii was found mostly from October to February; Ru. reversa and Ru. frontosa predominated in September. An. lutzi, Chagasia fajardoi, Coquillettidia chrysonotum, Aedes serratus, Trichoprosopon simile, Wyeomyia theobaldi, Ru. humboldti, and Ru. theobaldi are the second most prevalent species and they were found mostly throughout the hottest, rainiest and most humid months. Temperature and rainfall have positively influenced the incidence of the majority of the species. CONCLUSIONS: The exuberant and well-preserved tropical forest of Mata Atlântica, rainfalls, and temperatures had a direct and significant contribution to the mosquito fauna in the park. In the months with greater rainfalls, temperatures and humidity, there was an increase in the density and diversity of mosquito species. The period from September to March was the most favorable for their proliferation. In the colder and drier period, from April to August, about 70% of the species showed a significant decline in number, and they were hardly found during these months.

Animals↗

PubMed2001

[Hemodynamic and respiratory changes in athletes during deep breath-hold diving].

BACKGROUND: The study analysed the hemodynamic and respiratory aspects of deep breath-hold diving. METHODS: One male (59-year-old) and one female (32-year-old) subject were enrolled. They were both champion deep breath-hold divers. The dives were performed in the wet compartment of the hyperbaric chamber, first in thermoneutral (35 degrees C) and then cool (25 degrees C) water. The subjects were monitored using ECG recordings; percentage cannulation of the right radial artery using an aseptic technique. Stroke volume (SV) and cardiac output (CO) were measured using impedance cardiography (Bomed). RESULTS: Variations were observed in heart rhythm, cardiac output, arterial blood pressure and breathing. Both bradycardia and many hemodynamically effective dysrhythmias influenced CO, which showed a tendency to decrease in the diver in cool water. Changes in CO were caused by concomitant changes in HR as SV showed no significant variations. During breath-hold diving, a drop in intra-thoracic pressure is likely to enhance redistribution of blood from the periphery to the chest, which might distend the heart even more, contributing to dysrhythmogenesis. The observation that dysrhythmias were more frequent in cool water is in line with these concepts. CONCLUSIONS: Only two leading divers were recruited in this study and observed for hemodynamic and respiratory changes. However, these findings are in line with similar studies carried out by other authors.

Adult↗

PubMed2000

Immunofluorescence distribution of actin-associated proteins in human seminiferous tubules of adolescent testes, normal and pathologic.

The aim of our study on human seminiferous tubules of adolescent testes was to study the localization of two actin-associated proteins of the adherens junctions, such as vinculin and talin, and to verify if there were modifications in their pattern in varicocele, a frequent disease of the testis in adolescent age. The study group consisted of 8 biopsies from normal testes (i.e., adolescents operated on for hydrocele or inguinal hernia) and 20 biopsies from pathological testes (i.e., adolescents operated on for idiophatic left varicocele). Biopsies were evaluated by indirect immunofluorescence using anti-human vinculin and anti-human talin antibodies. Observation was recorded with a Leica TCS 4D upright confocal microscope. In the normal testes, there was a strong positive immunoreactivity for vinculin, which was localized in the interstitial cells of Leydig, and both basal pole and lateral cell surface of Sertoli cells; the pattern of talin immunoreactivity was the same except that the lateral cell surface of Sertoli cells was not stained. In the varicocele group the pattern was different. Vinculin immunoreactivity showed small patches of fluorescence only in the cytoplasm of Sertoli cells while talin immunoreactivity showed a scanty distribution at the basal surface of Sertoli cells. These results confirm that, similarly to other tissues, vinculin is expressed at cell-cell and cell-matrix adherens junctions, while talin is present at cell-matrix adherens junctions in human seminiferous tubules of normal adolescents. Varicocele alters the patterns of these two proteins both quantitatively and qualitatively.

Adherens Junctions↗

PubMed2000

Myofibroblasts in adolescent varicocele: an ultrastructural and immunohistochemical study.

Myofibroblasts of the testes play an important role in the morphofunctional integrity of the seminiferous tubule. Previous studies in adults with varicocele have demonstrated an involvement of this cell population that tends to transform into fibroblasts. The aim of the present study was to try and verify the morphological features of myofibroblasts in the adolescent with left idiophatic varicocele. Twenty-two testicular biopsies were obtained from adolescents (aged 13-18 years, mean 15.8) and operated for left idiophatic varicocele. Biopsies were processed for electron microscopy (TEM) and immunofluorescence studies. The latter determined the level of myofibroblasts by using alpha-smooth muscle isoactin, a specific marker of myofibroblasts and, hence, excluding fibroblasts. TEM observations revealed a normal ultrastructure of myofibroblasts that was similar to that for the controls but an increased presence of extracellular matrix. The immunofluorescence study always demonstrated strong cell positivity to anti alpha-smooth muscle isoactin as also seen in the controls. This study demonstrates that adolescents with varicocele have well preserved myofibroblasts and do not show any evidence of transformation into fibroblasts, this has already been demonstrated in adult varicocele. These observations could represent an important factor for the understanding of the reversal of growth failure of the testes observed after early treatment.

Adolescent↗

PubMed2000

Ultrastructural and immunohistochemical study of basal lamina of the testis in adolescent varicocele.

OBJECTIVE: To evaluate a possible involvement of the extracellular matrix (ECM) in the testes of adolescents with varicocele. DESIGN: Cross-sectional study. SETTING: University-based medical center. PATIENT(S): Twenty-four adolescents aged between 13 and 18 years underwent surgical treatment for repair of left idiopathic varicocele. INTERVENTION: A testis biopsy was performed at time of surgery. MAIN OUTCOME MEASURE(S): Transmission electron microscopy study of basal lamina and immunofluorescence studies of collagen type IV and laminin, two major components of basal lamina. RESULT(S): Transmission electron microscopy observations showed an uneven profile of the basal lamina with a variable thickness. Immunofluorescence studies showed an irregular immunofluorescent line that appeared interrupted in some observations. Collagen type IV showed some areas of strong immunostaining with other areas with reduced immunoreactivity. CONCLUSION(S): Our ultrastructural and immunohistochemical observations highlight focal damage at the level of peritubular basal lamina, but this damage is not as severe as that described in adult varicocele. Initial involvement of basal lamina could represent one of the mechanisms responsible for varicocele-induced histologic alterations of the testes.

Adolescent↗